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Schneier writes: "Now that we have enough details about how the NSA eavesdrops on the internet, including today's disclosures of the NSA's deliberate weakening of cryptographic systems, we can finally start to figure out how to protect ourselves."

Schneier: 'Trust the math. Encryption is your friend. That's how you can remain secure even in the face of the NSA.' (photo: Beck Diefenbach/Reuters)
Schneier: 'Trust the math. Encryption is your friend. That's how you can remain secure even in the face of the NSA.' (photo: Beck Diefenbach/Reuters)

How to Stay Secure Against the NSA

By Bruce Schneier, Guardian UK

07 September 13


ow that we have enough details about how the NSA eavesdrops on the internet, including today's disclosures of the NSA's deliberate weakening of cryptographic systems, we can finally start to figure out how to protect ourselves.

For the past two weeks, I have been working with the Guardian on NSA stories, and have read hundreds of top-secret NSA documents provided by whistleblower Edward Snowden. I wasn't part of today's story - it was in process well before I showed up - but everything I read confirms what the Guardian is reporting.

At this point, I feel I can provide some advice for keeping secure against such an adversary.

The primary way the NSA eavesdrops on internet communications is in the network. That's where their capabilities best scale. They have invested in enormous programs to automatically collect and analyze network traffic. Anything that requires them to attack individual endpoint computers is significantly more costly and risky for them, and they will do those things carefully and sparingly.

Leveraging its secret agreements with telecommunications companies - all the US and UK ones, and many other "partners" around the world - the NSA gets access to the communications trunks that move internet traffic. In cases where it doesn't have that sort of friendly access, it does its best to surreptitiously monitor communications channels: tapping undersea cables, intercepting satellite communications, and so on.

That's an enormous amount of data, and the NSA has equivalently enormous capabilities to quickly sift through it all, looking for interesting traffic. "Interesting" can be defined in many ways: by the source, the destination, the content, the individuals involved, and so on. This data is funneled into the vast NSA system for future analysis.

The NSA collects much more metadata about internet traffic: who is talking to whom, when, how much, and by what mode of communication. Metadata is a lot easier to store and analyze than content. It can be extremely personal to the individual, and is enormously valuable intelligence.

The Systems Intelligence Directorate is in charge of data collection, and the resources it devotes to this is staggering. I read status report after status report about these programs, discussing capabilities, operational details, planned upgrades, and so on. Each individual problem - recovering electronic signals from fiber, keeping up with the terabyte streams as they go by, filtering out the interesting stuff - has its own group dedicated to solving it. Its reach is global.

The NSA also attacks network devices directly: routers, switches, firewalls, etc. Most of these devices have surveillance capabilities already built in; the trick is to surreptitiously turn them on. This is an especially fruitful avenue of attack; routers are updated less frequently, tend not to have security software installed on them, and are generally ignored as a vulnerability.

The NSA also devotes considerable resources to attacking endpoint computers. This kind of thing is done by its TAO - Tailored Access Operations - group. TAO has a menu of exploits it can serve up against your computer - whether you're running Windows, Mac OS, Linux, iOS, or something else - and a variety of tricks to get them on to your computer. Your anti-virus software won't detect them, and you'd have trouble finding them even if you knew where to look. These are hacker tools designed by hackers with an essentially unlimited budget. What I took away from reading the Snowden documents was that if the NSA wants in to your computer, it's in. Period.

The NSA deals with any encrypted data it encounters more by subverting the underlying cryptography than by leveraging any secret mathematical breakthroughs. First, there's a lot of bad cryptography out there. If it finds an internet connection protected by MS-CHAP, for example, that's easy to break and recover the key. It exploits poorly chosen user passwords, using the same dictionary attacks hackers use in the unclassified world.

As was revealed today, the NSA also works with security product vendors to ensure that commercial encryption products are broken in secret ways that only it knows about. We know this has happened historically: CryptoAG and Lotus Notes are the most public examples, and there is evidence of a back door in Windows. A few people have told me some recent stories about their experiences, and I plan to write about them soon. Basically, the NSA asks companies to subtly change their products in undetectable ways: making the random number generator less random, leaking the key somehow, adding a common exponent to a public-key exchange protocol, and so on. If the back door is discovered, it's explained away as a mistake. And as we now know, the NSA has enjoyed enormous success from this program.

TAO also hacks into computers to recover long-term keys. So if you're running a VPN that uses a complex shared secret to protect your data and the NSA decides it cares, it might try to steal that secret. This kind of thing is only done against high-value targets.

How do you communicate securely against such an adversary? Snowden said it in an online Q&A soon after he made his first document public: "Encryption works. Properly implemented strong crypto systems are one of the few things that you can rely on."

I believe this is true, despite today's revelations and tantalizing hints of "groundbreaking cryptanalytic capabilities" made by James Clapper, the director of national intelligence in another top-secret document. Those capabilities involve deliberately weakening the cryptography.

Snowden's follow-on sentence is equally important: "Unfortunately, endpoint security is so terrifically weak that NSA can frequently find ways around it."

Endpoint means the software you're using, the computer you're using it on, and the local network you're using it in. If the NSA can modify the encryption algorithm or drop a Trojan on your computer, all the cryptography in the world doesn't matter at all. If you want to remain secure against the NSA, you need to do your best to ensure that the encryption can operate unimpeded.

With all this in mind, I have five pieces of advice:

  1. Hide in the network. Implement hidden services. Use Tor to anonymize yourself. Yes, the NSA targets Tor users, but it's work for them. The less obvious you are, the safer you are.
  2. Encrypt your communications. Use TLS. Use IPsec. Again, while it's true that the NSA targets encrypted connections - and it may have explicit exploits against these protocols - you're much better protected than if you communicate in the clear.
  3. Assume that while your computer can be compromised, it would take work and risk on the part of the NSA - so it probably isn't. If you have something really important, use an air gap. Since I started working with the Snowden documents, I bought a new computer that has never been connected to the internet. If I want to transfer a file, I encrypt the file on the secure computer and walk it over to my internet computer, using a USB stick. To decrypt something, I reverse the process. This might not be bulletproof, but it's pretty good.
  4. Be suspicious of commercial encryption software, especially from large vendors. My guess is that most encryption products from large US companies have NSA-friendly back doors, and many foreign ones probably do as well. It's prudent to assume that foreign products also have foreign-installed backdoors. Closed-source software is easier for the NSA to backdoor than open-source software. Systems relying on master secrets are vulnerable to the NSA, through either legal or more clandestine means.
  5. Try to use public-domain encryption that has to be compatible with other implementations. For example, it's harder for the NSA to backdoor TLS than BitLocker, because any vendor's TLS has to be compatible with every other vendor's TLS, while BitLocker only has to be compatible with itself, giving the NSA a lot more freedom to make changes. And because BitLocker is proprietary, it's far less likely those changes will be discovered. Prefer symmetric cryptography over public-key cryptography. Prefer conventional discrete-log-based systems over elliptic-curve systems; the latter have constants that the NSA influences when they can.

Since I started working with Snowden's documents, I have been using GPG, Silent Circle, Tails, OTR, TrueCrypt, BleachBit, and a few other things I'm not going to write about. There's an undocumented encryption feature in my Password Safe program from the command line); I've been using that as well.

I understand that most of this is impossible for the typical internet user. Even I don't use all these tools for most everything I am working on. And I'm still primarily on Windows, unfortunately. Linux would be safer.

The NSA has turned the fabric of the internet into a vast surveillance platform, but they are not magical. They're limited by the same economic realities as the rest of us, and our best defense is to make surveillance of us as expensive as possible.

Trust the math. Encryption is your friend. Use it well, and do your best to ensure that nothing can compromise it. That's how you can remain secure even in the face of the NSA. your social media marketing partner


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+9 # DaveM 2013-09-07 09:56
One suggestion: there is, as I understand it, a list of "key words" that various intelligence agencies look for in intercepts. I believe that list is available publicly. Copy and paste that list as your e-mail signature, post it on Facebook, etc. etc. The NSA and related agencies may have virtually unlimited ability to collect data, but their human resources to make use of collected data are finite. Throw all those words out there (make a few variations as a simple cut and paste could be easily screened out), and it just might be possible to jam the system.

A few well-meaning spammers could accomplish a lot here.
+5 # Malcolm 2013-09-07 11:30
I like this idea. Would you be able to post this list for us? That would be truly marvy!
+3 # Trueblue Democrat 2013-09-08 13:47
Good idea, DaveM.

Now on the lighter side, recalling a bumper sticker that showed up not long after George W. Bush was "elected" -- BUSH IS LISTENING. USE BIG WORDS.

+3 # m... 2013-09-07 10:24
''ow that we have enough details about how the NSA eavesdrops on the internet, including today's disclosures of the NSA's deliberate weakening of cryptographic systems, we can finally start to figure out how to protect ourselves.''--

I would like to add the following to the end of that statement...

-- from the For-Profit Private Contractors which are now operating our National Security System in order to turn a profit however they can without breaking the shady laws supposedly regulating their business operations.
-8 # Milarepa 2013-09-07 10:32
Good advice, thanks. I'm not a computer geek, so encrypting is too difficult and time-consuming for me. I've asked myself if it may be true that I have nothing to hide and the answer is Yes, I have nothing to hide. EXCEPT. Except my thoughts. And actually, when I examine what I'm thinking, I notice that I lean over backwards to accommodate even people I think are doing awful things. My dodge is that I believe we all have a truly individualistic destiny and purpose while alive. All of us, from the worst to the best. So NSA or no NSA I got nothing to worry about.
+8 # Candide 2013-09-07 11:21
Many thanks to Bruce Schneier, the Guardian and RSN for this defense of privacy and our Bill of Rights. I'll share, too, another purifying ritual: When words like "recover" are used to describe theft, as in "recovering electronic signals from fiber" or "defense industry" for arms industry or merchants of death, we have not held off the contaminating symbols that subvert our communications. As Noam Chomsky has said, "when they changed the name of the War Department to 'Defense Department' you knew it wasn't about defense any more. If I were a journalist, I'd ask my editor to set her or his word processing program to highlight words like "defense" for review, or better yet, set my own computer to highlight them to defend against faulty content.
+2 # lorenbliss 2013-09-07 14:22
Mr. Schneier's piece is a classic example of the economic discrimination built into digital technology and the utter, even sociopathic indifference of the Nurdish world to the harsh realities of class warfare.

For most of us – for nearly everyone in the 99 Percent – encryption is impossibly expensive. The people who need encryption most – those involved in union organizing or any other genuine grass-roots effort at building Working Class resistance – are forever denied its vital protection.

Indeed, that is precisely why successful resistance is not only futile but literally impossible: it costs too much money. In other words, the advent of the computer has priced us out of any rational hope for even limited democracy.

Clearly, this was the intent from the very beginning. Computers are – and always have been – the perfect tool of capitalist oppression, protests of the ignorant fools who stupidly believe there is such a thing as “benign” or “beneficial” capitalism not withstanding.

Quite simply, computers were invented as instruments of enslavement, and with the advent of total-surveilla nce tyranny, that is the ultimate purpose they now fulfill.
+1 # hsfrey 2013-09-07 15:50
Re lorenbliss' complaint:

There are plenty of free open source encryption programs available.

What's missing is the incentive and perhaps intellectual ability to use it.

Surely there's Someone in the "99%" who can figure out how to do so, and show the lorenblisses how.
+3 # lorenbliss 2013-09-07 16:40
"Open source" encryption programs are by definition compromised by their very nature. "Open Source" means available to everyone -- including the cryptographers of NSA and all the other USian secret police agencies.

Beyond that, hsfrey's assertion, "what's missing is the incentive and perhaps the intellectual ability..." is a classic example of Nurdish arrogance and Ayn Rand indifference to the realities of class warfare. Indeed my thanks to hsfrey for so vividly illustrating my point.
+1 # Granny Weatherwax 2013-09-09 10:44
I have to disagree with that.

If anything, open source means you can have a look at the code to check whether there is a backdoor in there and the sanity of the math. Then you can compile yourself that very same source you checked into a program that you can use and trust.

On the other hand, proprietary software you have to buy ($$$) and no, you can't have a look at what it is actually doing. For all you know it could sift through your data right there and send a digest directly to Foggy Bottom.

Yes it takes understanding and effort, and no, not everyone can do it.
But hsfrey is right.
+2 # rhgreen 2013-09-08 06:31
Re. internet privacy, I don't really worry about it, except for $$ transactions and I use the secure transaction methods the banks etc. provide. I don't care if the US and Cdn govt know what I think of them. If they want to arrest me then I'll just make it as public as possible when they do. But I think it's good for everyone to make the spying as difficult and expensive as possible for NSA to do.
0 # Milarepa 2013-09-09 10:05
Let it go and move on!

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